%UMFPACK_SIMPLE a simple demo
  %
  % Example:
  %   umfpack_simple
  %
  % Copyright 1995-2007 by Timothy A. Davis.
  %
  % UMFPACK License:
  %
  %     Your use or distribution of UMFPACK or any modified version of
  %     UMFPACK implies that you agree to this License.  UMFPACK is
  %     is free software; you can redistribute it and/or
  %     modify it under the terms of the GNU Lesser General Public
  %     License as published by the Free Software Foundation; either
  %     version 2.1 of the License, or (at your option) any later version.
  
  % Availability: http://www.cise.ufl.edu/research/sparse/umfpack
  %
  % See also: umfpack, umfpack2, umfpack_details
  
  help umfpack_simple
  
  format short
  
  A = [
   2  3  0  0  0
   3  0  4  0  6
   0 -1 -3  2  0
   0  0  1  0  0
   0  4  2  0  1
  ] ;
  fprintf ('A = 
  ') ; disp (A) ;
  
  A = sparse (A) ;
  
  b = [8 45 -3 3 19]' ;
  fprintf ('b = 
  ') ; disp (b) ;
  
  fprintf ('Solution to Ax=b via UMFPACK:
  ') ;
  fprintf ('x1 = umfpack2 (A, ''\\'', b)
  ') ;
  
  x1 = umfpack2 (A, '\', b) ;
  fprintf ('x1 = 
  ') ; disp (x1) ;
  
  fprintf ('Solution to Ax=b via MATLAB:
  ') ;
  fprintf ('x2 = A\\b
  ') ;
  
  x2 = A\b ;
  fprintf ('x2 = 
  ') ; disp (x2) ;
  
  fprintf ('norm (x1-x2) should be small: %g
  ', norm (x1-x2)) ;
  
  fprintf ('Type ''umfpack_demo'' for a full demo of UMFPACK
  ') ;